FindFirst() might not work correctly

[cmelchior]

Copy from: #826 (comment)

I see that this was merged into master in february. But I think I am still have issues related to different results from findFirst() and findAll().first()

I have a RealmResults which I further want to query: mAllUsersForCompany is of type RealmResults:

The following works. It gives me a user whos name has length of three and who was in the mAllUsersForCompany list:

mAllUsersForCompany.where().equalTo("nameLength", 3).findAll().first()
But the following seems to completely ignore the additional equalTo constraint and gives me a user which has namelength != 3

mAllUsersForCompany.where().equalTo("nameLength", 3).findFirst()

[cmelchior]

Hi @gillde
I tried to reproduce the behaviour described here, but it looks fine to me. Can you provide code samples or a sample project with a reproducible error?

[cmelchior]

We cannot reproduce this behaviour, so closing. Please reopen if there is any new information about this.

[kevinvanmierlo]

I'd like to reopen this. I found a way to reproduce this behaviour.

Game:

public class Game extends RealmObject
{
    @PrimaryKey
    private long id;

    private long levelId;

    public long getId()
    {
        return id;
    }

    public void setId(long id)
    {
        this.id = id;
    }

    public long getLevelId()
    {
        return levelId;
    }

    public void setLevelId(long levelId)
    {
        this.levelId = levelId;
    }
}

GameState:

public class GameState extends RealmObject
{
    @PrimaryKey
    private long id;

    private long levelId;

    public long getId()
    {
        return id;
    }

    public void setId(long id)
    {
        this.id = id;
    }

    public long getLevelId()
    {
        return levelId;
    }

    public void setLevelId(long levelId)
    {
        this.levelId = levelId;
    }
}

MainActivity:

        Realm realm  = Realm.getInstance(this);

        realm.beginTransaction();
        for(int i = 0; i < 10; i++)
        {
            Game game = new Game();
            game.setId(i);
            game.setLevelId(1);
            realm.copyToRealmOrUpdate(game);
        }
        realm.commitTransaction();

        realm.beginTransaction();
        for(int i = 11; i < 20; i++)
        {
            Game game = new Game();
            game.setId(i);
            game.setLevelId(2);
            realm.copyToRealmOrUpdate(game);
        }
        realm.commitTransaction();

        RealmResults<Game> games = realm.where(Game.class).equalTo("levelId", 2).findAll();

        RealmResults<GameState> gameStates = realm.where(GameState.class).equalTo("levelId", 2).findAll();
        if(gameStates.size() < games.size())
        {
            for(Game game : games)
            {
                if(gameStates.where().equalTo("id", game.getId()).count() == 0)
                {
                    realm.beginTransaction();
                    GameState stateGame = new GameState();
                    stateGame.setId(game.getId());
                    stateGame.setLevelId(game.getLevelId());
                    realm.copyToRealm(stateGame);
                    realm.commitTransaction();
                }
            }
        }

        gameStates = realm.where(GameState.class).equalTo("levelId", 2).findAll();
        for(Game game : games)
        {
            GameState gameState = gameStates.where().equalTo("id", game.getId()).findFirst();
            GameState gameState1 = gameStates.where().equalTo("id", game.getId()).findAll().first();

            Log.d("TAG", "gameState: " + gameState + " | gameState1: " + gameState1);
        }

These are the results:

05-22 09:52:27.807  19230-19230/? D/TAG﹕ gameState: GameState = [{id:0},{levelId:1}] | gameState1: GameState = [{id:11},{levelId:2}]
05-22 09:52:27.807  19230-19230/? D/TAG﹕ gameState: GameState = [{id:1},{levelId:1}] | gameState1: GameState = [{id:12},{levelId:2}]
05-22 09:52:27.808  19230-19230/? D/TAG﹕ gameState: GameState = [{id:2},{levelId:1}] | gameState1: GameState = [{id:13},{levelId:2}]
05-22 09:52:27.808  19230-19230/? D/TAG﹕ gameState: GameState = [{id:3},{levelId:1}] | gameState1: GameState = [{id:14},{levelId:2}]
05-22 09:52:27.808  19230-19230/? D/TAG﹕ gameState: GameState = [{id:4},{levelId:1}] | gameState1: GameState = [{id:15},{levelId:2}]
05-22 09:52:27.808  19230-19230/? D/TAG﹕ gameState: GameState = [{id:5},{levelId:1}] | gameState1: GameState = [{id:16},{levelId:2}]
05-22 09:52:27.808  19230-19230/? D/TAG﹕ gameState: GameState = [{id:6},{levelId:1}] | gameState1: GameState = [{id:17},{levelId:2}]
05-22 09:52:27.808  19230-19230/? D/TAG﹕ gameState: GameState = [{id:7},{levelId:1}] | gameState1: GameState = [{id:18},{levelId:2}]
05-22 09:52:27.808  19230-19230/? D/TAG﹕ gameState: GameState = [{id:8},{levelId:1}] | gameState1: GameState = [{id:19},{levelId:2}]

I hope this is enough information to find the problem. Nasty one to reproduce, but this particular case went wrong with my game.

[cmelchior]

Hi @kevinvanmierlo
Thank you very much for this info. We will take a look at it.

[cmelchior]

Hi @kevinvanmierlo
I have tried to reproduce the above error but cannot. I am getting the following output:

05-29 05:48:03.187  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:11},{levelId:2}] | gameState1: GameState = [{id:11},{levelId:2}]
05-29 05:48:03.187  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:12},{levelId:2}] | gameState1: GameState = [{id:12},{levelId:2}]
05-29 05:48:03.187  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:13},{levelId:2}] | gameState1: GameState = [{id:13},{levelId:2}]
05-29 05:48:03.188  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:14},{levelId:2}] | gameState1: GameState = [{id:14},{levelId:2}]
05-29 05:48:03.188  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:15},{levelId:2}] | gameState1: GameState = [{id:15},{levelId:2}]
05-29 05:48:03.188  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:16},{levelId:2}] | gameState1: GameState = [{id:16},{levelId:2}]
05-29 05:48:03.188  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:17},{levelId:2}] | gameState1: GameState = [{id:17},{levelId:2}]
05-29 05:48:03.188  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:18},{levelId:2}] | gameState1: GameState = [{id:18},{levelId:2}]
05-29 05:48:03.188  22193-22193/io.realm.examples.intro D/TAG﹕ gameState: GameState = [{id:19},{levelId:2}] | gameState1: GameState = [{id:19},{levelId:2}]
05-2

Which should be correct. What version of Realm are you testing against?

[kevinvanmierlo]

@cmelchior I'm using 0.80.3. I always test on Genymotion with lollipop. The weird thing is when I just tested it on my normal device it worked as expected while on Genymotion it gives back the wrong result.

[cmelchior]

That sounds really odd, because I usually run these tests on the same setup. Can you possibly share the full sample project so I am absolutely sure I don't do anything different on my end?

[kevinvanmierlo]

@cmelchior sure! I'm grabbing some lunch first and then I'll share it with you.

[kevinvanmierlo]

@cmelchior I pushed the sample project to GitHub. You can find it here.
Also I'm using Genymotion 2.4.0 free version. Hope this helps.

[cmelchior]

This is really strange. I cannot reproduce your behaviour even when using the same project on Genymotion 2.4 with a Nexus 5 - 5.1.0 emulator. Do you only see this error on Genymotion but not on your device / Android emulator?

[kevinvanmierlo]

Actually I'm using the Google Nexus 5 - 5.0.0 - API 21 Genymotion. So perhaps that's the difference. The system has 4 processors and the Base Memory is 2048 MB. I don't see the error on my device (5.0) or emulator(5.0.1). I don't really know why the error only appears on this specific configuration.

Edit: The error also doesn't show on my Genymotion 2.4 with Nexus 5 - 5.1.0 emulator

[cmelchior]

Hi @kevinvanmierlo
I tried to reproduce it on the exact same GenyMotion image as you, but it still shows the correct result for me. Have you tried deleting your image and creating a new one?

[kevinvanmierlo]

@cmelchior After deleting and creating a new one, this also worked. Very weird that it happened though. Thanks for the quick responses!

[cmelchior]

Yes, it is a bit strange. It might be a bit late, but if you still has a copy of a Realm file where this error occurred it would be nice to see it. Perhaps we can see what was wrong with it?

[kevinvanmierlo]

@cmelchior I deleted the emulator, so no way of getting that back. I should've backed it up. I'll see if I can recreate the error somehow.

[cmelchior]

Thanks. If you manage to reproduce it please send the file to [email protected]. In the meantime I'll close this issue.